The invention is concerned with application of individual numbers to products such as hand-held electronic calculators, in such a way as to allow changing of a number when necessary.
There are a number of situations wherein each of a series of similar or identical items needs to be uniquely identified, so that all of the items in the collection can be accounted for. One situation where this holds true is in schools, where electronic calculators are used, but not owned, by a class of students. When the calculators are turned in to the teacher, if a calculator is missing or broken it should be known who is responsible. Thus, teachers have often used felt tip pens or paint to put a number on the back of each of a collection of student calculators, such as numbers 1 through 30. This practice has some disadvantages: the wearing off of the ink or paint, the time required for applying the numbers, the possibility that students could change the numbers using a similar pen, etc.
Another possibility is the use of stick-on labels, but again, these are subject to tampering and peeling off by students, and a supply of printed labels, with multiple copies of the same numbers, would have to be maintained by the teacher.
For these reasons, it would be desirable if the manufacturer would apply a unique number to each of a group of calculators intended for a school class. However, this is difficult from the point of view of the manufacturer, not only because a different number must be silk-screened, embossed, etched or otherwise applied to each calculator, but also because the number of calculators ordered for different schools and classes varies, causing obvious problems of stock and inventory. Also, if a calculator from a particular class is lost or broken, and a replacement calculator is ordered, the manufacturer would have to provide a replacement calculator bearing the same number as the calculator to be replaced, again with obvious problems of inventory and cost.
There has been no economical and convenient solution to this problem of identifying individual classroom calculators, as well as other, similar situations wherein a series of identical items are lent to students or other groups, until the present invention described below.